The field of the invention is rotary die-cutting for use in the converting of corrugated and solid-fiber paper board or other like materials.
Rotary die-cutters are used to process a variety of paper products, and are particularly used to cut, score, and crease paper box packaging materials including corrugated cardboard. The die-cutters operate by the interaction of a die-cutting tool, which is affixed onto a die-cutting cylinder, and an anvil. Typically, the die-cutter is used in a process where corrugated paper board passes through a nip formed between a rotating die-cutting cylinder affixed with a cutting tool and an opposing anvil.
Tools or forms are generally fitted to the exterior of the die-cutting cylinder to create a creasing profile or cut into the board. The cuts and creases are formed when the face of the tool is forced through or against the board as it passes through the nip between the anvil and the die-cutting cylinder. The resulting board contains the appropriate creases and cuts. The creased and cut board advances out of the die-cutter through the use of collars, rollers, belts, vacuum belts, or other equivalent means.
As is typical in the industry, the die-cutters are operated on a batch, or order system, wherein numerous orders are run throughout the day. During operation of the die-cutter, it is generally necessary to change the tool located on the exterior of the die-cutting cylinder for each order. Since the tools are generally fastened to the die-cutting cylinder by multiple bolts, the removal and securing of the cutting tools on the die-cutting cylinder can be a time-consuming process. Even when more sophisticated mounting systems or apparatus are used to fasten tools to the die-cutting cylinder, the replacement of the tool on the die-cutting cylinder still requires time, during which the die-cutter cannot be operated. Typically, this process takes from ten to twenty-five minutes in current die-cutter machines. Given that ten or more orders per day are commonly run within the industry, such downtime can reach in excess of four hours per day, or approximately half of the day's production time.
It is generally preferable to have the die-cutting cylinder located above the anvil cylinder so that die-cut scrap that is produced is ejected downwards towards the floor and away from the product. However, if the die-cut cylinder is located above the anvil, any printing that is done will be performed below the board line, since printing is generally done on the side opposite the scores and creases. This creates a problem, however, in that when the die-cutting cylinder is placed at its ideal height, i.e., waist level, the print cylinder is at an undesirable lower level such as thigh height. This lower position is undesirable as printing plates located on the exterior of the printing cylinders are typically equal to the length of the circumference of the printing cylinder and are mounted on a thin, flexible clear plastic such that they hang down. However, for quality printing, it is essential to keep the printing plate clean and undamaged. Consequently, having a location for the printing cylinder suspended well above the floor level (e.g., shoulder height) permits an operator to walk to the printer and mount the printing plate with ease. While the printing cylinder could be raised to waist height, the die-cutting cylinder would have to move correspondingly higher to a position that is awkward and undesirable from an operational perspective.
Consequently, there is a need to create a die-cutter capable of near-continuous operation that increases the productivity of the equipment and process. That is, a need for a machine that allows the cutting tool to be set-up while the die-cutter is actually in operation, producing product with the major cylinders that require tool mounting (print cylinders and die-cut cylinder) to be at more suitable located heights for the operator.